Which of the following is not a component of the time series?

A time series is data collected over different time periods. When analyzing time series data, it is broken down into different components to understand patterns.

The 4 standard components of time series are:

Trend Component (T): The long-term direction of data, showing upward or downward movement over time. Example: Population increasing every year or company sales growing over a decade.

Cyclical Component (C): Up and down movements that repeat over long periods, usually more than one year. Example: Economic boom and recession cycles. These patterns take years to complete and are less predictable than seasonal patterns.

Seasonal Component (S): Regular patterns that repeat at fixed intervals of less than one year. Example: Ice cream sales high in summer and low in winter, repeating annually.

Irregular Component (I): Unpredictable random variations caused by unexpected events. Example: Natural disasters, strikes, or sudden market changes.

The standard time series model is represented as:

$Y = T \times C \times S \times I$ (multiplicative model)

or

$Y = T + C + S + I$ (additive model)

"Average Component" is not a recognized component in time series analysis. Average is simply a statistical measure (mean value), not a pattern or variation in the data itself. It does not appear in the standard decomposition of time series.

Therefore, the answer is Option 4 - Average Component is not a component of time series.